Anyone know how to fix this?

I’m using a Flsun Q5. I keep getting these small gaps in my infill. I wouldn’t really care if I just wanted a print that looks good on the outside but now I’d like to start printing my own custom parts for rc cars/planes and I need these parts to be durable but I don’t want to have to make everything with 100% infill cause that would just be a waste. Also I’ve been having a bit of a stringing issue if anyone has ideas to fix that, I’ve tried messing with the nozzle temp with little success, I’m not to worried about the stringing through mainly the gaps in infill. I’m fairly new to 3d printing so any help is welcome!